16 June 2011

The decimation of Atlantic food fish

Jilted lovers used to be consoled by friends with the reassurance that "there are plenty more fish in the sea."  That analogy may not be valid much longer.  Here are some excerpts from a column in the Guardian's Datablog:
This image shows the biomass of popularly-eaten fish in the North Atlantic Ocean in 1900 and in 2000...

Dr Villy Christensen and his colleagues at the University Of British Columbia used ecosystem models, underwater terrain maps, fish catch records and statistical analysis to render the biomass of Atlantic fish at various points this century...

These early accounts and data on the past abundance of fish help reveal the magnitude of today's fish stock declines which are otherwise abstract or invisible.

They also help counter the phenomenon of "shifting environment baselines". This is when each generation views the environment they remember from their youth as "natural" and normal... The problem is, the sea was already heavily exploited when we were young. So this is a kind of collective social amnesia that allows over-exploitation to creep up and increase decade-by-decade without anyone truly questioning it...

As Prof Roberts writes: "The greater part of the decline of many exploited populations happened before the birth of anyone living today."
The study itself was published in Fish and Fisheries in 2003. Here's part of the abstract -
We estimate the biomass of high-trophic level fishes in the North Atlantic... from 1880 to 1998. We extract over 7800 data points that describe the abundance of high-trophic level fishes as a function of year, primary production, depth, temperature, latitude, ice cover and catch composition.We then use a multiple linear regression to predict the spatial abundance for all North Atlantic spatial cells for 1900 and for each year from 1950 to 1999. The results indicate that the biomass of high-trophic level fishes has declined by two-thirds during the last 50-year period, and with a factor of nine over the century. Catches of high- trophic level fishes increased from 2.4 to 4.7 million tonnes annually in the late 1960s, and subsequently declined to below 2 million tonnes annually in the late 1990s... Our results raise serious concern for the future of the North Atlantic as a diverse, healthy ecosystem; we may soon be left with only low-trophic level species in the sea.
Writing this post has reminded me that I need to revisit my review of the excellent book Paradise Found: Nature in America at the Time of Discovery, by Steve Nicholls.  I wrote one post about the topic last year, but there's much more amazing information to present.


  1. If no one can own a resource, there is no reason to preserve the capital stock. If everyone can access but none can own, the competition will only be in terms of who can exploit the good first. The result is predictable.

    Murray Rothbard commented on this way back in 1986 (I believe it is in this lecture at about 6:00):


    Daniel Hannan comments (succinctly) on the same:


    I hope you will consider listening.

  2. What a good comment post, 032125. Thank you!

  3. I was going to carp about your use of the word decimate, but I see the definition has evolved.

    Kill, destroy, or remove a large percentage or part of

    - the project would decimate the fragile wetland wilderness
    - the American chestnut, a species decimated by blight

    Drastically reduce the strength or effectiveness of (something)

    - plant viruses that can decimate yields

    Kill one in every ten of (a group of soldiers or others) as a punishment for the whole group

  4. Thanks,Sue. I floundered around trying to fix it, then decided to write another post on the subject.


  5. A very sad state of affairs. when I was a teenager I remember going with my father to some of the main fishing ports of the north-east of england, seeing the hundreds of trawlers there, bound for, or returning from arctic waters. Then came the "Cod War", where Iceland unilaterally increased the area its territorial waters and sought to stop other nations from fishing there.
    The truth is that Iceland predicted, correctly, the decline in fish stocks, and sought to act to prevent overfishing. European union fishery protection policy was a nonsense. Each country vied to scoop more and more fish from the seas. Quotas and minimum net sizes were established. But it's been proven that taking the bigger fish and leaving the smaller does not work as a safeguard to fish stocks. leaving big no-go areas might work. Artificial reefs might work. Perhaps. Modern fishing led to nets which sweep along the seabed, and take, destroy everything in their path. Including the fish it's illegal to land. So they're chucked back over the side. Not landed, or sold, but dead anyway.
    And right up until recent times, people in the industry refused to believe they could ever destroy the very thing they harvested. The Grand Banks cod, once so plentiful, is all but gone.
    Damn humans, despoilers.

    I can, with clear conscience, say that none of the blame can be laid at my door.
    I'm allergic to fish. I have no part in the cod-killing guilt, because I've never eaten one.

  6. Giant schools of fish have been replaced by giant schools of jellyfish, and plastic waste. And no one has the slightest clue why...

    Perhaps it's a naturally occurring cycle- like what happened to the buffalo.

  7. http://www.huffingtonpost.com/2011/06/20/ipso-2011-ocean-report-mass-extinction_n_880656.html


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